Frequent changes in the operating modes pose significant challenges in the development of a pump-turbine with high efficiency and stability. In the current publication on Investigation on Flow Characteristics of Pump-Turbine Runners With Large Blade Lean in the Journal of Fluids Engineering, two pump-turbine runners, one with a large positive blade lean and the other with a large negative lean, are investigated numerically and experimentally. These two runners are designed by using the optimum stacking condition at the high pressure edge (HPE). The experimental and the numerical results show interesting outcomes on efficiency performances and pressure fluctuations. The internal flow field analyses clarify the effects of the blade lean on the pressure distribution around the runner blades. In the turbine mode at partial load, the negative blade lean can control flow separation in the high pressure side of the runner and then reduce the pressure fluctuations in the vaneless space.
Pumped storage power stations are experiencing rapid development in China with the increasing development of smart grid and extensive development of nuclear and wind power stations for renewable energy. As a key component of the mechanical part of pumped storage power stations, the reversible pump-turbine has the function of water pumping and electricity generation as the load varies in the electricity grid. High efficiency, no cavitation, and good stability are important standards to evaluate the performance of a pump turbine unit. Compared with the efficiency and cavitation, it is difficult to evaluate the hydraulic stability due to its unstable characteristics in the design stage.